• Title/Summary/Keyword: average separation

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A Study on Dynamic Separation of Silica Slurry Using a Rotating Membrane Filter: Transient State and Steady State (회전막 여과기를 사용한 실리카 슬러리의 동역학적 분리에 대한 연구: 과도기와 정상 상태)

  • 박진용;최창균;김재진
    • Proceedings of the Membrane Society of Korea Conference
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    • 1992.10a
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    • pp.53-54
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    • 1992
  • In this study characteristics of dynamic filters utilizing Taylor vortices were investigated both experimentally and theoretically. With fine silica slurry of 4.0 $\mu$m in average size experiments were conducted in Taylor vortices generated between the rotating inner cylinder consisting of microfiltration membrane of 1.2 $\mu$m in average pore size and the stationary outer cylinder. The diameter of the inner cylinder was 5.2 cm. Four outer cylinders having different diameters were manufactured and therefore four types of dynamic filters having the different ratio of the annular gap to the inner cylinder radius, i.e. 0.17, 0.33, 0.54, 0.65, were used as the experimental apparatus, as shown in Fig. 1.

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A Development of an Evaluation System for Traffic Calming Schemes (교통정온화사업 평가체계 개발에 관한 연구)

  • Park, Wan-Yong;Won, Jai-Mu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.4D
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    • pp.335-343
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    • 2012
  • In the study, evaluation indicators that should be considered in applying traffic calming schemes were developed, and it was intended to analyze the importance of indicators that should most considered in evaluation traffic calming scheme through AHP analysis on the basis of it. The result of the study is summarized as follows. The result of evaluation indicators may be summarized by dividing into residential area and commercial area. In category, the safety is shown to be more important than other indicators in the analysis when evaluation (residential area is 0.514 and commercial area is 0.439). Importance of evaluation indicators was analyzed in order Average Vehicle Speed, Traffic Accident Severity, and Pedestrian Separation. Residential areas to help keep the safety of pedestrians 'Average Vehicle Speed' as the major indices were derived. In commercial areas were analyzed as an important indicator Pedestrian Separation. Because there are so many pedestrians. When applying the effect of Traffic Calming, residential is greater than the commercial area.

Hospital's Financing Behaviors Based on Comparative Analysis of Trade-off Theory and Pecking Order Theory (상충관계이론과 자본조달순위이론에 기초한 병원 자본조달행태 분석)

  • Kim, Jai-Myung;Ham, U-Sang;Ahn, Young-Chang
    • Korea Journal of Hospital Management
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    • v.11 no.2
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    • pp.61-86
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    • 2006
  • Based on a previous literature about hospital capital structure(Shyam- Sunder & Myers, 1999), this study attempted comparison and analysis on whether the forecast of trade-off and pecking order theory could be validated in hospital's capital structure. First, this study analyzed whether hospitals follow the priority for each capital source as suggested by pecking order theory under lack of capital running in hospital. Next, it analyzed whether debt level is regressed on the average to target debt level so as to verify the validity of trade-off theory. Finally, it also analyzed possible associations between debt level and determinants of capital structure as adopted in static trade-off theory, so as to verify relative advantages of these two theories about hospital capital structure. The analysis over whole period showed that both trade-off theory and pecking order theory isn't supported particularly. This mean that each hospital's financing behaviors is different and that has not dominant financing behaviors. In the midst of separation of dispensary from medical practice, medical institutions in Korea first finances funds required using retained earnings and then use liabilities. however pecking order theory is supported, the preference of long-term liabilities and short-term liabilities is not clear. In addition, considering that debt level is in no average regression to target debt ratio, it is found that hospital capital structure following trade-off theory turns into that subject to pecking order theory via the separation of dispensary from medical practice.

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Old Water Contributions to a Granitic Watershed, Dorim-cheon, Seoul

  • Kim, Hyerin;Cho, Sung-Hyun;Lee, Dongguen;Jung, Youn-Young;Kim, Young-Hee;Koh, Dong-Chan;Lee, Jeonghoon
    • Journal of Soil and Groundwater Environment
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    • v.20 no.5
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    • pp.34-40
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    • 2015
  • It is reported that the intensity of rainfall will likely increase, on average, over the world on 2000. For water resources security, many studies for flow paths from rainfall or snowmelt to subsurface have been conducted. In Korea, few isotopic studies for characterizations of flow path have been undertaken. For a better understanding of how water derived from atmosphere moves to subsurface and from subsurface to stream, an analysis of precipitation and stream water using oxygen-18 and deuterium isotopes in a small watershed, Dorim-cheon, Seoul, was conducted with high resolution data. Variations of oxygen-18 in precipitation greater than 10‰ (δ18Omax = −1.21‰, δ18Omin = −11.23) were observed. Isotopic compositions of old water (groundwater) assumed as the stream water collected in advance were −8.98‰ and −61.85‰ for oxygen and hydrogen, respectively. Using a two-component mixing model, hydrograph separation of the stream water in Dorim-cheon was conducted based on weighted mean value of δ18O. As a result, except of instant dominance of rainfall, contribution of old water was dominant during the study period. On average, 71.3% of the old water and 28.7% of rainfall contributed to the stream water. The results show that even in the small watershed, which is covered with thin soil layer in granite mountain region, the stream water is considerably influenced by old water inflow rather than rainfall.

Computational Flow Analysis on Wind Profile Change Projected to a Wind Turbine Behind Saemangeum Seawall (새만금 방조제에 의한 풍력터빈 입사풍 변화의 전산유동해석)

  • Woo, Sang-Woo;Kim, Hyun-Goo
    • New & Renewable Energy
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    • v.9 no.1
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    • pp.6-11
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    • 2013
  • Jeollabuk-do has announced a future plan for the Saemangeum Wind Farm which includes the installation of fourteen wind turbines in a single line, located 500m back from the Saemangeum Seawall. It is anticipated as a positive effect that, for sea breeze blowing toward land, the average wind speed could be accelerated and the wind speed distribution could be uniformized by dint of the seawall, an upstream structure of the turbines. At the same time it is also anticipated as a negative effect that the strength of wind turbulence could be increased due to the flow separation generated at the back end of the seawall. According to the results of the computational fluid dynamics analysis of this paper, it has been observed that, at the 50m zone on the road surface located at the uppermost part of the Saemangeum Seawall, the average wind speed has been accelerated by approximately 6~7% and that wind shear has been decreased by 70%, but this positive effect disappears in the zone situated beyond the 100m from the back end of the seawall. It has also been observed that flow separation exists to a limited extent only below the bottom of the blade-sweeping circle and, furthermore, does not extend very far downstream of the wind. As a conclusion, it can be said that the seawall neither positively nor negatively affects the proposed Saemangeum Seawall Wind Farm layout.

Field Assessment of Food Safety Management at Preschool Foodservice Establishments (영유아 급식소 위생관리 수행도 현장평가)

  • Bae, Hyun-Joo;Lee, Hye-Yeon;Ryu, Kyung
    • Korean journal of food and cookery science
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    • v.25 no.3
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    • pp.283-296
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    • 2009
  • This study examined food safety management at preschool establishments in Daegu and Gyeongbuk province, to provide data that can be used for food safety improvements. Field assessments of 60 foodservice establishments were executed from July to October, 2007. Statistical analyses of the data were conducted using the SPSS package program (version 14.0 for windows). The results are summarized as follows: 93.3% of the preschool foodservices were self-operated, and 24.1% of the child care centers and 96.7% of the kindergartens had employed dietitians. According to the averaged food safety evaluation scores the kindergartens (80.73) had a significantly higher score than the child care centers (50.37), and the public centers (85.00) had a significantly higher score than the private centers (54.29). While the average score of facilities that employed dietitian (73.58) was significantly higher than that of facilities that did not employ a dietitian (52.65). In addition, the average score of facilities that served meals in a dining room (80.83) was significantly higher than that of facilities that served meals in a classroom (59.33). The highest scoring food safety items included verifying employee health inspection reports (1.87), utilizing non-municipal water and routinely cleaning and well-maintaining the water storage tank (1.85), and disposing small amounts of leftovers in a vat after serving (1.83). In contrast, the lowest scores were for physical separation of clean areas and unclean areas to prevent cross-contamination (0.52), and physical separation between staff and food material entry areas (0.62). In conclusion, the preschool foodservice evaluated in this study required improvements in food safety management, and many of the child care centers were in need of immediate attention. To improve food safety at these establishments, administrators should implement prerequisite food safety programs.

DETERMINATION OF THE TRANSURANIC ELEMENTS INVENTORY IN HIGH BURNUP PWR SPENT FUEL SAMPLES BY ALPHA SPECTROMETRY

  • Joe, Kih-Soo;Song, Byung-Chul;Kim, Young-Bok;Han, Sun-Ho;Jeon, Young-Shin;Jung, Euo-Chang;Jee, Kwang-Yong
    • Nuclear Engineering and Technology
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    • v.39 no.5
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    • pp.673-682
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    • 2007
  • The contents of transuranic elements in high-burnup spent fuel samples were determined. The activity amounts of $^{238}Pu,\;^{239}Pu,\;^{240}Pu,\;^{241}Am,\;^{244}Cm\;and\;^{242}Cm$ were measured by alpha spectrometry using $^{242}Pu\;and\;^{243}Am$ as tracers, respectively. A spike addition method for $^{237}Np$ was established by an alpha and gamma spectrometry using $^{239}Np$ as a spike after the optimum conditions for the measurements of $^{237}Np\;and\;^{239}Np$, respectively, were obtained. A separation system using anion exchange chromatography and diethylhexylphosphoric acid extraction chromatography was applied for the separation of these elements. This method was applied to high-burnup spent nuclear fuel samples $(40{\sim}60GWD/MTU)$. The contents of the transuranic elements were compared with those by ORIGEN-2 code. Measurements and the calculations of the contents of the plutonium isotopes $^{238}Pu,\;^{239}Pu\;and\;^{240}Pu$ agreed to within 10% on average. The contents of $^{237}Np$ agreed to within approximately 5% except for one instance of a calculation, while those of $^{241}Am,\;^{244}Cm\;and\;^{242}Cm$ showed higher values by approximately 19%, 35% and 14% on average, respectively, compared to the calculations according to the burnup.

Coulometric Determination of Plutonium in PWR Spent Fuels (PWR 사용후핵연료내 플루토늄의 전기량적 정량)

  • Sohn, Se Chul;Suh, Moo Yul;Kim, Jung Suk;Song, Byung Chul;Jee, Kwang Yong;Choi,In Kyu;Kim, Won Ho
    • Journal of the Korean Chemical Society
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    • v.44 no.6
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    • pp.581-586
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    • 2000
  • Separation and coulometric titration method were applied for the determination of plutonium content in samples of PWR spent fuel. Plutonium was separated on an anion exchange(AG MP-1) column and determined by the controlled-potential coulometric titration. In this study, we discussed some experimental conditions related to the separation and determination of plutonium in PWR spent fuel samples. Average accuracy(recovery of plutonium) for the determination of 0.230∼3.02 mg plutonium standard was 99.36%. Average precision(relative standard deviation, RSD) for the determination of 0.250∼0.450 mg plutonium in PWR spent fuel samples was 0.38%.

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Prescription Pattern for a Simulated Patient With the Common Cold at Pharmacies in a Region in Korea Without Separation of Dispensary From Medical Practice (영동지방 의약분업 예외지역 약국들에서의 감기 증상 모의 환자에 대한 약물 처방 현황)

  • Lee, Hyeong-Cheol;Park, Woo-Joo;Oh, Mi-Kyeong
    • The Korean Journal of Health Service Management
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    • v.13 no.3
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    • pp.115-125
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    • 2019
  • Objectives: Korea has been practicing the separation of dispensary from medical practice since 2000 as a national policy to prevent misuse or overuse of medicines. This study aimed to investigate prescription patterns from except pharmacies in order to determine the appropriateness of drug usage among those patients. Methods: Thirty-two pharmacies in the Yeongdong area of Gangwon Province were examined in this study. The same simulated patient complaining of cold symptoms for 3 days visited each pharmacy to obtain a prescription for medication. Results: At pharmacies prescribing medicine, steroids (53.1%) and antibiotics (50.0%) were used to treat the common cold. Duplicate prescriptions of drugs, such as antihistamines (47.0%) and decongestants (31.3%) were common. The average number of drug prescriptions was 6.59, and 53.2% of pharmacies had prescribed more than seven drugs. The average total cost of the prescriptions was 6,093 won, and the daily cost was 2,544 won. Conclusions: Steroids and antibiotics were frequently abused among patients whose medications had been prescribed by pharmacies. Also, there were a considerable number of drugs and duplicate prescriptions. The prices of the drugs were somewhat high.

Characteristics of Coagulants Distribution by the Pumping Rate in Pump Diffusion Mixer (Pump Diffusion Mixer에서 압력수량에 따른 응집제 확산분포 특성)

  • Park, Youngoh;Kim, Ki-Don;Park, No-Suk;Lim, Jae-Lim;Lim, Kyung-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.1
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    • pp.65-71
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    • 2008
  • This study collected the latest 30-year (1976~2005) continuous rainfall data hourly recorded at 61 meterological observatories in Korea, and the continuous rainfall data was divided into individual rainfall events. In addition, distribution charts of average rainfall event-depth were created to facilitate the application to the overflow risk-based design of detention storage basin. This study shows that 4 hour is appropriate for SST (storm separation time) to separate individual rainfall events from the continuous rainfall data, and the one-parameter exponential distribution is suitable for the frequency distribution of rainfall event depths for the domestic rainfall data. The analysis of the domestic rainfall data using SST of 4 hour showed that the individual rainfall event was 1380 to 2031 times, the average rainfall event-depth was 19.1 to 32.4mm, and ranged between 0.877 and 0.926. Distribution charts of average rainfall event-depth were created for 4hour and 6 hour of SST, respectively. The inland Gyeongsangbuk-do, Western coastal area and inland of Jeollabuk-do had relatively lower average rainfall event-depth, whereas Southern coastal area, such as Namhae, Yeosu, and Jeju-do had relatively higher average rainfall event-depth.